1. Field of the Invention
The following description relates to transport layer control technology of an Internet protocol, and more particularly, to a transport layer control device, a method for transmitting a packet, and a method for receiving a packet using both transmission control protocol (TCP) and user datagram protocol (UDP) characteristics.
2. Discussion of the Background
FIG. 1 shows a hierarchical structure of an Internet protocol. As shown in FIG. 1, the Internet protocol includes five layers: a physical layer, a data link layer, a network layer, a transport layer, and an application layer. Thus, the Internet protocol differs from an open systems interconnect (OSI)-7 layer model.
As representative protocols of the transport layer, there are a transmission control protocol (TCP) and a user datagram protocol (UDP). The TCP is a protocol in which a lost packet is re-transmitted to a receiving device, so that more reliable packet transmission is performed. That is, the TCP is a connection-oriented protocol designed to perform a re-transmission mechanism and a congestion control mechanism under the assumption that a transmission error such as packet loss occurs due to a network error.
The UDP is a connectionless protocol, does not perform a complicated control operation such as retransmission or congestion control, does not perform a response acknowledge operation, and merely provides a UDP header error detection function, which is a minimum error control function. Therefore, the UDP does not guarantee reliability of packet transmission. However, the UDP may improve a transmission rate and transmission efficiency relative to TCP due to its simpler operating characteristics.
That is, the TCP may provide better reliability but has lower transmission efficiency, while the UDP may provide a higher data transmission rate but does not guarantee reliability. Due to such characteristics, the TCP is generally used in applications that require more reliable packet transmission such as file transfer protocol (FTP), while the UDP is generally used in applications that require a constant transmission rate even though some packets may be lost. But there is no single protocol or transmission/reception method that offers the benefits of both TCP and UDP.